Metal-coordinated distibene and dibismuthene dications - isoelectronic analogues of butadiene dications.

We report the synthesis and solid-state structures of DMAP-coordinated ([L(DMAP)GaPn]2 [OTf]2 ; Pn = Sb 3, Bi 4) and base-free dipnictene dications ([LGaPn]2 [BArF x ]2 , Pn = Sb: x = 24, 5a; 20, 5b; Bi: x = 24, 6a; 20, 6b). Quantum chemical calculations indicate that the dications 52+ and 62+ represent isoelectronic analogues of the butadiene dication.